Low plasma free choline is prevalent in patients receiving long term parenteral nutrition and is associated with hepatic aminotransferase abnormalities

Abstract

Hepatic transaminase abnormalities have been previously reported in patients receiving long term total parenteral nutrition (PN). We sought to determine if such abnormalities are caused by choline deficiency-induced hepatocyte damage. In 41 subjects (19 male, 22 female) aged 45.1 ± 24.3 years (range 0.1–79 years) who have received PN for 5.5 ± 4.7 years (range 0.1–14.5 years). We determined plasma free and phospholipid bound choline levels, serum albumin, ALT and AST. We also determined the daily volume of intravenous lipid emulsion received by the patients as well as the concentration of free choline and phospholipid bound choline in the lipid emulsion. Plasma free choline was low in 33 41 subjects (mean 7.15 ± 2.5 nmol/ml, range 3.3–15.6, normal 11.4 ± 3.7). Phospholipid bound choline was normal in 34 41 subjects (mean 2157 ± 620 nmol/ml, range 1026–3887, normal 2364 ± 774). Elevations in ALT and AST were significantly correlated with plasma free choline (r = −0.34, p = 0.03, r = −0.37, p = 0.02 respectively) but not with phospholipid bound choline. No relationship was found between age, PN duration or daily volume of intravenous lipid and plasma free or phospholipid bound choline. The lipid emulsion contained 24 ± 6 nmol/ml of free choline and 11 630 ± 552 nmol/ml of phospholipid bound choline. We conclude that low plasma free choline is prevalent in patients receiving long term PN and this abnormality is associated with elevated serum aminotransferases. Furthermore, intravenous lipid emulsion is an inadequate source of choline for this patient group.